Zillow has spent years building relationships with thousands of litigious MLS's. It's impossible to build a lawsuit-proof real-estate app in the US without doing that.

They partner with Listhub and pay for the data feed, and/or get deals with individual MLSs and large brokerages. Hopefully, for folks in the UK it’s not as awful as it is in the states.

Zillow, OpenDoor, Redfin, and Realtor.com all pay for API access to the largest Multiple Listing Systems (except for Realtor because they are the ones that are selling the access).

They then use their own “special” algorithms to give their price estimate based on “relevant” factors by what you are describing.

Your real issue is that the agents putting these homes on the market have a financial stake in it selling, and own copyright to all the pictures and descriptions of their listings. So you have more liability if you are scraping their info.

Another issue is who is the target audience for this? Most serious homebuyers are going to use an agent or a trusted partner for a transaction, and are not excited about compounding layers of hurdles to purchase a home

I am a residential real estate appraiser in the US and real estate technologist, which is why I bring up these points.

There’s not an MLS equivalent in the UK, property data is quite fragmented.

We’re not looking to display anything an estate agent doesn’t want us to - agents tell us they’re very happy for us to serve as an advertising channel. And we’d immediately action any sort of take down request.

I was on the real state listing site side long time ago, we were trying to block scrapers from getting our data, at the en we loss, and now we pay them to send us users instead of paying Google ads because it’s cheaper. Fun times